Triclosan Promotes Conjugative Transfer of Antibiotic Resistance Genes to Opportunistic Pathogens in Environmental Microbiome

Abstract

Although triclosan, as a widely used antiseptic chemical, is known to promote the transmission of antibiotic resistance to diverse hosts in pure culture, it is still unclear whether and how triclosan could affect the transmission of broad-host-range plasmids among complex microbial communities. Here, bacterial culturing, fluorescence-based cell sorting, and high-throughput 16S rRNA gene amplicon sequencing were combined to investigate contributions of triclosan on the transfer rate and range of an IncP-type plasmid from a proteobacterial donor to an activated sludge microbiome. Our results demonstrate that triclosan significantly enhances the conjugative transfer of the RP4 plasmid among activated sludge communities at environmentally relevant concentrations. High-throughput 16S rRNA gene sequencing on sorted transconjugants demonstrates that triclosan not only promoted the intergenera transfer but also the intragenera transfer of the RP4 plasmid among activated sludge communities. Moreover, triclosan mediated the transfer of the RP4 plasmid to opportunistic human pathogens, for example, Legionella spp. The mechanism of triclosan-mediated conjugative transfer is primarily associated with excessive oxidative stress, followed by increased membrane permeability and provoked SOS response. Our findings offer insights into the impacts of triclosan on the dissemination of antibiotic resistance in the aquatic environmental microbiome.

Phthalates Promote Dissemination of Antibiotic Resistance Genes: An Overlooked Environmental Risk

“…coli HB101) on the selection plates to exclude spontaneous mutation to produce false transconjugants. For the wastewater microbiota conjugation system, flow cytometric cell detection (CytoFLEX,Beckman Coulter, USA) was performed to quantify the number of transconjugants based on the number of green fluorescent cells . The excitation and emission wavelengths were set as: 561-614/42 ( dsRed ), and 488-525/40 ( gfp ).…”

“…For the wastewater microbiota conjugation system, flow cytometric cell detection (CytoFLEX,Beckman Coulter, USA) was performed to quantify the number of transconjugants based on the number of green fluorescent cells. 29 The excitation and emission wavelengths were set as: 561-614/42 (dsRed), and 488-525/40 (gf p). To identify the community structure of transconjugants in wastewater microbiota, the transconjugants were subjected to fluorescence-activated cell sorting (FACS) (BD FACS Aria III, USA).…”

Underestimated Risks of Microplastics on the Environmental Spread of Antibiotic Resistance Genes

“…For example, the plastic additive triclosan can cause aquatoxicity and promote the conjugative ARGs transfer to opportunistic pathogens in activated sludge microbiome. Therefore, chemicals released from microplastics pose a realistic threat to One Health by accelerating ARGs spreading . For example, the marine environments contaminated by a mixture of MPs and chemical additives have been demonstrated to coselect antibiotic resistance in bacterial pathogens and transmit it to humans through seafood .…”

“…Therefore, chemicals released from microplastics pose a realistic threat to One Health by accelerating ARGs spreading. 18 For example, the marine environments contaminated by a mixture of MPs and chemical additives have been demonstrated to coselect antibiotic resistance in bacterial pathogens and transmit it to humans through seafood. 4 However, the detailed impacts of these plastic chemical additives and the underlying biological mechanisms underpinning the accelerated ARGs spreading remain ambiguous.…”

Comamonas resistens sp. nov. and Pseudomonas triclosanedens sp. nov., two members of the phylum Pseudomonadota isolated from the wastewater treatment system of a pharmaceutical factory

“…Triclosan (5-chloro-2-(2′,4′-dichlorophenoxy) phenol; TCS), a type of broad-spectrum antimicrobial and PPCP, has been widely distributed in the aquatic environment, especially since the coronavirus disease 2019 (COVID-19) pandemic [30]. Compared to antibiotics, non-antibiotic antiseptic products are not subject to prescription, and their consumption has surged during the COVID-19 pandemic with the raising global awareness of sanitation, which could threaten public and environmental health by promoting the propagation of antimicrobial resistance [31,32]. Previous studies have demonstrated that TCS at environmentally relevant concentrations can stimulate the horizontal gene transfer (HGT) of antibiotic-resistance genes (ARGs) [33][34][35].…”